Smart traffic lights enable greater control of the traffic flow reducing congestion and making journeys shorter and safer.
Smart traffic lights enable greater control of the traffic flow reducing congestion and making journeys shorter and safer.
( Source: gemeinfrei / Unsplash)

SMART TRAFFIC Smart traffic lights create roads that respond to user needs

Author / Editor: Cate Lawrence / Isabell Page

Smart traffic lights make the roads more responsive to the needs of users, improve traffic flow, reduce accidents, and lower carbon emissions. However as technology evolves. the need for a security-first approach is critical to ensure safety on the streets.

As road users, we often feel as if the traffic is conspiring against us. If you've ever waited at three lanes of traffic lights during peak hour and manage to get every red light or hate crossing a road where you never quite make it across both pedestrian crossings even if you run, then you'll understand the frustration felt by many.

Fortunately, the efforts of smart city planning provide a layer of technological innovation to ease traffic and congestion woes and reduce accidents. A critical component is smart traffic lights.

What are smart traffic lights?

Traditional traffic lights are programmed to change signals at predetermined times, such as typical peak hours. By comparison, smart traffic systems acquire data from the road users and communicate with a central control system to change lights and signal lengths as needed. Smart traffic control systems primarily consist of:

  • A central control system
  • Smart traffic lights
  • Cameras and queue detectors

The cameras and queue detectors can monitor and inform the control system of real-time traffic conditions. In turn, the lights can respond according to the information, improving traffic flow, reducing congestion, prioritizing pedestrians and emergency vehicles.

What are the benefits of smart traffic lights?

There are several key initiatives and benefits to specific road users. Imagine a city where cyclists and pedestrians are given priority at traffic lights. The use of V2E (vehicle to everything) communication creates lights which are responsive rather than preset. Buses can communicate their position, number of passengers, and any delays to the traffic signals and will receive longer green lights when they are behind schedule or full of passengers. Emergency service vehicles are prioritized with green lights all the way. All of this is a possibility with smart traffic lights.

A combination of smart lights and route planning can reduce traffic jams, lower CO2 emissions and redistribute the flow of traffic. Provider NoTraffic optimizes traffic light grids with AI embedded sensors which can detect different travel modes such as cars, bikes, buses, or pedestrians — and changes the lights according to the needs of each. The platform then enables each city to implement traffic policies that maximize traffic flows and make the streets safer. The company recently installed its infrastructure in Phoenix, Arizona. In the near future, buses will receive priority based on capacity and time schedule while routing data from navigation apps, will be used to help divert traffic in real-time, based on origin-destination data of all road users.

Pedestrians prioritized

In Vienna, following two years of testing, intelligent traffic lights have been gradually replacing around 200 existing push-button traffic lights in the city. The lights are embedded with cameras which detect not only people but also whether they want to cross the road or not, in which case their journey is prioritized.

The city is also working to interconnect all traffic lights, enabling them to communicate with each other and to resolve unpredictable traffic jams caused by accidents or construction sites quicker. Also planned is a collaboration with the Central Institute for Meteorology and Geodynamics (ZAMG), to equip traffic lights with 10,000 weather and environmental sensors. The data creates the ability to identify heat islands and identify air pollutants as well as track noise - all essential components of smart city planning.

Smart traffic lights fight noise pollution

While smart traffic lights can reduce carbon emissions, they can also contribute to solving the problem of sound pollution. The Mumbai police conducted a trial last year in response to car honking by making people wait longer at the traffic lights if they honked their horn. Decibel meters were connected to traffic light poles, and if the meters registered noise levels of 85 decibels or over, the lights were reset and stayed red for longer.

Connected cars talk to traffic lights

In 2019, Audi introduced vehicle-to-infrastructure (V2I) service "Traffic Light Information" to Ingolstadt, Germany (the technology has been available in much of the US since 2016) with a larger roll out from this year. Audi drivers can see via the dashboard what speed is required to reach the next traffic light on green. If that is not possible within the permitted speed limit, there will be a countdown to the next green phase.

Audi predicts that in the future their customers may be enjoy added benefits such as cars which make increased use of braking energy to charge their batteries at red lights. They also predict that predictive adaptive cruise control could enable cars to even brake automatically at red lights.

Smart Bicycles lights point to a bigger problem

In the Netherlands, proof of concept trials have been carried out to prioritize green lights when bike riders approach. An example is the use of the mobile app Schwung, which once activated is connected to smart traffic lights. The app starts automatically upon cycling (no action is required of the rider) and traffic lights identify that you are approaching and turn green.

The lights for cyclists specifically have been recently criticized for security vulnerabilities, with security researchers Rik van Duijn and Wesley Neelen from security firm named Zolderat demonstrating their flaws at the recent DEFCON hacker conference. The hackers were able to trick the system into giving the green light to non-existent bicycles through feeding fake data into the apps.

In response, Talking Traffic, the initiative responsible for installing 1200 smart traffic lights across the Netherlands asserts "Those apps have been disconnected in the meantime, and the suppliers in question have promised to take measures in order to provide a better product in the near future." They also concede that the hack would be problematic if it meant the green lighting of lights in multiple directions.

The ease in which researchers were able to hack the app, highlights the need for a security-first approach to design and throughout testing and further implementation for all smart light initiatives. This is particularly important as we're already seeing a plethora of initiatives targeting different road users are coming from different companies, many with their own protocols and proprietary software - from patches to plug-ins and apps. How will we ensure all of these are appropriately secure (and remain so?)